How to have a single upload directory for a multiple sugarcrm instance on a differenct server sharing only one common databases?

Hello everyone, we are using multiple SugarCRM instances on a multiple server, with only one common database. Now, I want to have a single 'upload' directory across my all CRM instances, so anyone can access attachments without any issues. Kindly guide me on this, if it possible or you can suggest me some alternate options for this. Any help appreciated. Thank you all.